WASHINGTON (Reuters) -A U.S. House panel is investigating former President Donald Trump’s handling of White House records after 15 boxes of official documents were retrieved from his private Florida property in what lawmakers said was a potential serious violation of the law. House oversight panel chairwoman Carolyn Maloney on Thursday said she was “deeply concerned” the records were not promptly turned over to the National Archives when Trump’s term ended in January 2021 “and that they appear to have been removed from the White House in violation of the Presidential Records Act.” Maloney said…